Respiratory gas flow regulators



Jan. 10, 1961 u. F. STRATMAN 2,967,536

RESPIRATORY GAS FLOW REGULATORS Filed June 27, 1957 1' w I 48 H I l 55 I so 47 I 33 l 54 23 3 o 29 34 27 f 56 57 R I I I2 {J I I 5 i 'F l ii 20 FIG. I

INVENTOR. URBAN F. STRATMAN BY ATTORNEY Unite States Patent OfiFice 2,967,536 RESPIRATORY GAS FLOW REGULATORS Urban F. Stratman, Davenport, Iowa, assignor to The Bendix Corporation, a corporation of Delaware Filed June 27, 1957, Ser. No. 668,391 7 Claims. (Cl. 137-63) This invention relates to respiratory gas flow regulators and to inhalation demand responsive regulators in particular.

Such regulators are connected in respiratory gas supply circuits between the gas source and the users respirator. They include supply valve means for opening and closing the supply circuit, means to determine when the user is inhaling and exhaling, and means to cause or permit the valve means to open and close in accordance with inhalation and exhalation respectively. These conditions are determined by sensing pressure changes at the downstream or outlet side of the regulator; and the sensing means most commonly employed is a diaphragm which forms a wall of a pressure chamber. This chamber is connected by a passageway to the gas supply passage at or near the outlet so that the chamber pressure will vary in accordance with pressure at the outlet.

The pressure differential between normal inhalation suctionand exhalation pressure is not very great so that provision of a regulator which will respond properly to this small pressure differential is a diflicult problem. The provision of novel means for solving this problem is one object of the invention.

The problem will be solved if the change in pressure in the outlet can be amplified sufliciently in the pressure chamber; and another object of the invention is to provide such amplification. However, the pressure chamber and the supply outlet are connected together so that special means are required to provide a different pressure change in the pressure chamber than in the outlet; and the provision of such means is another object of the invention.

These objects are realized in the invention by the provision of means for utilizing the kinetic energy of respiratory gas flow both to increase pressure in the pressure chamber and to aspirate gas from it. The gas flow is divided into two streams, one of which is directed into the pressure chamber, and the other of which is directed toward the supply outlet and is arranged to aspirate gas from the pressure chamber. The two streams flow simultaneously when the supply valve is open but rather than simply opposing one another, it has been demonstrated that the aspirating stream acts, when the supply valve opens, to cause the valve opening to increase rapidly to the required degree, and that the other stream acts, when inhalation flow ceases, to build up pressure in the chamber rapidly whereby the supply valve is closed rapidl y.

Only during inhalation, when the supply valve must remain open and pressure at the outlet remains unchanged, do the effects of the two gas streams ofiset one another. The provision of means for producing such gas streams in the regulator is another object of the invention.

Other objects and advantages of the invention will be apparent in the following description of the drawing, it being understood that various modifications may be made in the embodiment shown and that other embodiments are possible without departing from the invention or the scope of the appended claims.

In the drawing:

Fig. 1 is a view in section-of a respiratory gas flow regulator embodying the invention, and

Fig. 2 is a top plan view of the nozzle employed in Fig. 1.

The regulator advantageously comprises a body, a respiratory gas supply passage in the body, supply valve means in the supply passage for opening and closing said passage, a pressure sensing chamber in the body having a pressure sensitive diaphragm in one wall of the chamber, a passage connection from the pressure chamber to the supply passage downstream from the valve means, and a leverage system by which movement of the diaphragm is made to actuate the supply valve. It further comprises means for utilizing the kinetic energy of respiratory gas flow for amplifying, in the pressure chamber, the pressure variations at the downstream side of the supply passage.

These elements are shown in a preferred form in the regulator selected for illustration in Fig. 1 wherein the body 10 is divided into upper and lower body sections 11 and 12 and a cover section 13.

The supply passage 14 is formed in the lower body section 12 where it begins at an inlet passage 15 and extends through a valve chamber 16 and a connecting passage 1'7 to a supply outlet passage 18 where it terminates at an outlet 18A which opens to the passage 19 of a hose connector 20 secured in any convenient manner, such as by bolts 21, to the lower body section 12.

The supply passage is opened and closed by a suitable valve of any well known type. A balanced valve is advantageously used because such valves are easily operated. The balanced valve 24 shown in valve chamber 16 is of a type well known in the art and the details of its construction are not important here except that the valve head 25 is moved toward and away from its seat 26 by axial movement of an actuating rod 23 fixed to head 25. This rod extends from valve head 25 through a low-friction sealing bushing 27, pressed into an opening 28 connecting the valve chamber with the upper face 290i body section 12, and into the central opening 30 of the upper body section 11.

Section 11 comprises a cylindrical wall 33 and an outwardly extending rectangular flange 34, and it is secured by any convenient means, to the upper face 29 of the lower body section. The cover 13 is cup-shaped; it is inverted and placed over the wall 33 of body section 11 so that its rim rests on flange 34 and so that its end wall 37 is spaced from the upper face 38 of section 11. The cylindrical side wall 39 of the cover surrounds the wall 33 and is separated therefrom by an annular sealing gasket The central opening 30 in upper body section 11 is covered by a circular pressure sensitive diaphragm assembly including a flexible diaphragm 45, supporting disks 46 and 47 overlying the central portion of the upper and lower faces of the diaphragm, and a clamping ring 48 which is held down by machine screws 49 to clamp the outer margin of the diaphragm 45 against the upper face 38 of the body section 11. The lower face of the diaphragm 4-5 is subjected to atmospheric pressure which is communicated to space 30 through a groove 32 formed in the lower face of the upper section 11 and connecting space 30 with the atmosphere.

The means for operating the balanced valve 24 in accordance with movement of diaphragm 45 may advantageously comprise, as shown, a pin 50 fixed to the center of the diaphragm assembly and extending into opening 30 where it is pivotally connected to one end of a lever 51. The other end of the lever is connected to a fixed pivot 54- secured to the upper face 29 of the lower body.

Patented Jan. 10, 196 1 51 by a pivot connector 55. Upon upward movement of diaphragm 45, pin 50 is carried upwardly, lever 51 is rotated counterclockwise about fixed pivot 54, and actuating rod 23 is moved upwardly to open the balanced supply valve 24. The action is reversed, of course, when the diaphragm is returned to the position shown.

In certain applications of the regulator, in particular when the respirator or face mask and the hoses connecting the regulator thereto might develop leaks, it is desirable to maintain a positive gas pressure at the regulator outlet. This feature is conveniently provided by the inclusion of means to bias the supply valve open and is advantageously provided here, as shown, by the addition of a safety pressure bias spring 56 retained in a recess 57 in the upper face 29 of body section 12 and bearing against the underside of lever 51 at its end opposite the fixed pivot 54.

The diaphragm 45 forms one wall of a pressure sensing chamber 60 which is further enclosed by the cover member 13 and the upper face 3-8 of body section 11. Means are provided in the invention for producing amplified pressure changes in this chamber which vary in accordance with pressure changes in the supply outlet 18. These means include pressure transmitting passage means connecting the pressure chamber to the supply passage downstream from the supply valve, means for directing a stream of gas into the pressure chamber, and means for aspirating gas from the pressure chamber when the supply valve is open. One portion of the stream of gas flowing through the supply passage is diverted toward the pressure chamber and another portion is passed through an aspirator arranged to aspirate gas from the pressure chamber through the passage means. Advantageously, two nozzles are employed in the supply passage to convert the stream of supply gas into jet streams; a first one is directed toward the pressure chamber and the other is directed toward the supply outlet from a point downstream from the pressure transmitting passage means. Moreover, the two nozzles are advantageously combined in a unitary double nozzle structure. Instead of providing separate passages by which said first jet stream is conducted to the pressure chamber and gas is aspirated from said chamber, a single passage may be employed, as shown.

In Fig. 1, the supply passage is enlarged at its outlet end passage 18 and a pressure communicating passage 61, formed in body sections 11 and 12, connects.the pressure chamber 60 to the outlet passage. A double nozzle 6?. is threaded into the supply passage upstream from the outlet passage 18 so that its front or downstream end projects into the outlet passage past the point at which the pressure transmitting passage 61 opens into the outlet passage 18. Its aspirating opening 63 opens at the front of the nozzle where it converts the stream of gas flowing in the supply passage into a high velocity or jet stream directed toward the outlet. The jet stream creates a pressure drop which aspirates gas from the pressure chamber 60. The other nozzle opening 64 is located at the side of the nozzle 62 opposite the opening of the pressure transmitting passage 61. It diverts gas flow from the supply passage and directs it in a high velocity or jet stream into the pressure transmitting passage 61 toward pressure chamber 69.

In operation of the regulator, assuming the mask user to be exhaling, the pressure in outlet passage 18, pressure transmitting passage 61 and pressure chamber 60 is sufliciently great to hold diaphragm 45 down and the valve 24 closed, as shown. In this condition there is no flow in the supply passage and no gas streams emerge from the nozzle 62. When the user begins to inhale, gas will be withdrawn from outlet passage 18, passage 61 and chamber 60 thereby reducing the pressure in cham ber 60 and allowing the safety pressure spring 56 and the atmospheric pressure in space 30 below the diaphragm 45 to lift the diaphragm and crack open the supply valve 24. Gas rushing past the valve toward the nozzle 62 is divided at the nozzle into two streams, one directed toward the pressure transmitting passage and the other or aspirating stream directed toward the outlet. The aspirating stream has the greater effect; it flows freely out of the regulator toward the inhaling user aspirating gas from chamber 60 and passage 61 including the gas flowing into passage 61 through the side opening 64 of the nozzle. The effect is to withdraw more gas from chamber 60 than the user could by his inhalation alone so that the diaphragm 45 is moved up and supply valve 24 is opened rapidly.

After the supply valve is opened to the required degree,

and for the remainder of the inhalation period, the pressures in the regulator will remain in dynamic balance. The flow from both nozzle openings will increase or decrease in the same proportion as the valve opening is varied, and whether the flow from the side opening 64 is immediately aspirated toward the outlet or will act to increase pressure in chamber 60, will depend upon the inhalation suction or resistance to flow experienced by the aspirating stream at the regulator outlet.

When inhalation ceases and exhalation begins, the pressure at the regulator outlet is built up rapidly to oppose the flow of the aspirating stream. The stream emerging from the side opening 64 is no longer aspirated but flows into the pressure communicating passage 61 toward the pressure chamber 60. Its kinetic energy and the pressure of the increased quantity of gas in said chamber, force the diaphragm 45 down rapidly to close the supply valve in substantially shorter time than would be required without the aid of the kinetic energy of the jet stream flowing through nozzle opening 64.

The regulator may be adjusted to provide a given degree of diaphragm displacement and supply valve opening for a given pressure at the regulator outlet by adjustment of the relative quantity of gas flow through the two nozzle openings; and the provision of this feature is another object of the invention. The means for adjusting the relative flows through these openings advantageously comprises, as shown, a split ring 65 made of spring material which embraces the nozzle body and can be slid back and forth along the body to cover a lesser or greater portion of the side opening 64. The adjustment need be made only once and is made using a tool such as a screw driver inserted down through the pressure transmitting passage when the regulator is factory-adjusted with cover 13 removed during calibration at a test stand.

I claim:

1. A respiratory gas flow regulator comprising a body, a gas supply passageway in the body originating at an inlet and terminating in a supply outlet, and means for regulating the flow of gas through said passageway, comprising a valve in the passageway, and means for operating the valve in accordance with pressure variations at the outlet, including a passage chamber connected to the outlet, a presssure responsive diaphragm in a wall of the chamber, valve actuating means connecting said valve and diaphragm and operated by the diaphragm for opening the valve when the chamber pressure is reduced and closing the valve when the chamber pressure is increased, means for increasing the drop in pressure in the chamber when outlet pressure is reduced, and means for increasing the rise in pressure in the chamber when the outlet pressure rises.

2. A respiratory gas flow regulator comprising a body, a gas supply passageway formed in said body originating at an inlet and terminating in a supply outlet, and means for regulating the flow of gas through said passageway comprising a valve in the passageway and means for operating the valve in accordance with pressure variations at the outlet, including a pressure chamber, passage means connecting said chamber to said passageway downstream from said valve, a pressure responsive diaphragm in a wall of the chamber, valve actuating means operated by the diaphragm for opening the valve when the chamber pressure is reduced and closing the valve when the chamber pressure is increased, and means for amplifying pressure changes in said chamber in accordance with pressure changes at said outlet, including aspirating means responsive to gas flow in said supply passageway for aspirating gas from said chamber through said passage means, and means upstream from said aspirator means for diverting some of the gas flowing in said supply passageway toward said chamber through said passage means.

3. A respiratory gas flow regulator comprising a body, a gas supply passageway formed in said body originating at an inlet and terminating in a supply outlet, and means for regulating the flow of gas through said passageway comprising a valve in the passageway and means for operating the valve in accordance with pressure variations at the outlet, including a pressure chamber, passage means connecting said chamber to said passageway downstream from said valve, a pressure responsive diaphragm in a wall of the chamber, valve actuating means operated by the diaphragm for opening the valve when the chamber pressure is reduced and closing the valve when the chamber pressure is increased, and means for providing more rapid actuation of said valve, including means for diverting a jet stream of gas from the supply passageway into said passage means toward the chamber, and nozzle means in said supply passageway for aspirating gas from said chamber in response to gas flow in said supply passageway.

4. A respiratory gas flow regulator comprising a body, a gas supply passageway in said body originating at an inlet and terminating in a supply outlet, and means for regulating the flow of gas through said passageway comprising a valve in the passageway and means for operating the valve in accordance with pressure variations at the outlet, including a pressure chamber, a pressure responsive diaphragm in a wall of the chamber, valve actu ating means operated by the diaphragm for opening the valve when the chamber pressure is reduced and closing the valve when the chamber pressure is increased, nozzle means in said passageway downstream from said valve for converting flow of gas in said supply passageway into two jet streams one of them directed toward said supply outlet, and means for aspirating gas from said chamber in accordance with flow velocity in the other jet stream including passage means connecting said chamber to said supply passageway at the upstream side of said one jet, stream and opening to said supply passageway in the path of said other jet stream.

5. The invention defined in claim 4 including means for adjusting the relative quantity of gas flow in said jet streams.

6. A respiratory gas flow regulator comprising a body, a gas supply passageway formed in said body originating at an inlet and terminating in a supply outlet, and means for regulating the flow of gas through said passageway comprising a valve in the passageway and means for operating the valve in accordance with pressure variations at the outlet, including a pressure chamber, passage means connecting said chamber to said passageway downstream from said valve, a pressure responsive diaphragm in a wall of the chamber, valve actuating means operated by the diaphragm for opening the valve when the chamber pressure is reduced and closing the valve when the chamber pressure is increased, and means including a first nozzle opening for diverting a jet stream of gas from said supply passageway into said passage means toward said chamber, and means including a second nozzle opening in said supply passageway for aspirating gas from said chamber in response to gas flow in said supply passageway.

7. The invention defined in claim 6 in which said second nozzle opening is located downstream in said supply passageway from said first nozzle opening, and in which said first nozzle opening is spaced from said passage means, whereby gas flowing through said first nozzle opening may be aspirated by fiow through the second nozzle opening without entering said passage means.

References Cited in the file of this patent UNITED STATES PATENTS Dec. 18, 1956 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent Nos 2,967,536 January 10, 1961 Urban Fa Stratman It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4 line 54 for "passage" read pressure Signed and sealed this 27th day of June 1961 (SEAL) Attest:

ERNEST W. SWIDER 7 DAVID L. LADD Attesting )fficer Commissioner of Patents 

